' 07 and up Harley-Davidsons, closed loop tuning capabilities?
Even if your EFI Harley-Davidson has closed loop running capabilities, the open loop areas need sampled and the ve tables needs calibrated during tuning to ensure that the VE tables are calibrated to the AFR/Lambda table.
When the ’07 closed loop capable Harley-Davidson motorcycles were released to the market, it was widely publicized that the closed loop capabilities provided by the o2 sensors would adjust for changes in air flow and there was no need to reflash the calibration on your motorcycle if you made changes like pipes and air cleaners. This was widely circulated in magazines and forums, but this is not correct.
Any one who changes the exhaust sysem, or even air filters alone, and expects the HD Delphi closed loop efi to account for the change in all areas of operation is literally playing with fire. The o2/lambda sensors do provide some adjustment, but the majority of corrections are made in the leaner cruise areas.
The HD closed loop system on the ’07 and up bikes only operates partially in closed loop. The typical cruise areas are maintained in closed loop, but the outside edges of the operating ranges are not. This means the wide open areas and decal areas operate in an open loop mode.
With the Harley Delphi fuel injection system, the open loop mode uses values that are permanently written to the base calibration to determine the fuel needs of the motorcycle. This means that any changes in airflow from what the base calibration values were developed from will result in those values being incorrect, if they were ever truly correct to begin with.
This becomes an issue every time a heavy load is placed on the bike, since the bike may see lean or rich values that could negatively affect the lifespan of your engine. The throttle point that the bike switches from closed to open throttle position is variable dependant on the rpm, the earlier rpm's reach the maximum MAP for closed loop before the higher rpm's. This means that simply heading up a steep hill at hi-way speeds at say 2,200-2,300 rpm could likely switch the bike from closed loop to open. If the airflow was increased by adding a free flowing air cleaner and free flowing mufflers, than this transition into open loop could result in an engine damaging lean condition.
On closed loop capable fuel injection Harley-Davidson motorcycles, Twins Cycle uses additional broad band o2 sensors installed in sensor blocks to sample afr while the bike remains in closed loop during tuning.
Our goal in dyno tuning is to adjust the ECM’s calibration to be based on the actual motorcycle to ensure a smooth transition from closed loop to open loop, and limit the amount of correction needed by the closed loop adjustments.
We calibrate the VE values in the open loop calibration settings to have a linear relationship with the afr/lambda tables in the calibration with settings that provide a nice blend of power and performance at wide open throttle. Ensuring these wide open afr/lambda values are with in a certain value is what promotes a nice broad torque curve.
After every closed loop tune, Twins Cycle verifies the open loop ve values ensuring that the ve tables are calibrated to the afr or lambda table.